I'm kind of with Pete Seeger who sang "Our leaders are the finest men, we elect them again and again". And I feel just as sarcastic as he did when he wrote this in "What did you learn in school today?"
Basically we elect those who bring home the bacon, those who look out for local interests even when not in the national interest. And we've been doing it for over 200 years to the dismay of many of the writers of the Constitution. See "The Radicalization of the American Revolution", Gordon S. Wood.
For a more lengthy screed on this conflict of interest, see "I don't blame Congress; I blame you!", Andrew Heaton.
